Devices used to securely transport paper currency are offered in many forms and styles from sturdy metal cases to locked nylon zipper bags. In recent years, a number of more sophisticated cash carrying devices have been introduced that add indelible ink deployment mechanisms to devalue currency in the event of theft. Additionally, electronic controls with tamper detection sensors have been employed to detect theft. These solutions involve elaborate ink delivery systems and limited electronic monitoring capabilities resulting in heavy and expensive cash carrying devices.
In a series of patents and patent applications, Villiger discloses cash carrying devices that have a mechanism for devaluing the currency based on signals from protection circuitry whose parameters are configured over a communication link to an interfacing piece of equipment. in U.S. Pat. No. 8,054,183, Villiger teaches a cash carrier system in which a portable computer travels alongside the cash carrier to authenticate the credentials of the cash handlers and to determine when the cash carrier should be armed and disarmed. A similar system is described in Villiger's U.S. Patent Application Publication No. 2011/0155026, in which a security cassette comprising a cash devaluing agent and tamper detecting sensors, is interfaced via an optical link with an optical transmitter for the purpose of setting security parameters which may include arm/disarm information or location information. Additionally, in Villiger's U.S. Pat. No. 7,707,950, a system is disclosed in which a cash strongbox area is interfaced to a removable handle portion that contains a security circuit that communicates to an electronic protection module inside the strongbox through a communication link within the interface.
In the above disclosed systems, a separate interface forms a critical portion of the security system. Those interfaces require the use of external hardware or specialized mechanical interlocks that call attention to the carrier personnel. Without the use of the interfacing hardware, the cash transport system's capabilities are significantly limited.
Another series of products relates to equipping standard transport cases, such as briefcases, with cash security systems. Villiger U.S. Patent Application Publication No. 2009/0235847 discusses a kit that can be installed in a case that consists of a pressurized ink deployment mechanism and associated security circuitry to arm, disarm, and detect tampering attempts.
These types of retrofit kits attempt to protect a large volume of interior case space through the use of large amounts of ink, pressurized air, and distributor plates to direct the pressurized ink to the interior space. Pressurized air deployment systems like those described by Villiger as well as by Lopez in U.S. Pat. No. 5,598,793, require the use of specially designed air tight valves and igniters or solenoids which result in a mechanically complicated and heavy solution. The air canisters are also vulnerable to leakage over time which would render the product ineffective upon loss of adequate air pressure to suitably deploy the ink.
Besides the use of pressurized air canisters, another approach to ink deployment involves the use of blade assemblies to open ink pouches. Lindskog describes a system in U.S. Pat. No. 6,564,726 in which an ink pouch is slit open in a guillotine fashion. Dyson follows a similar guillotine approach in U.S. Pat. No. 7,281,477, but adds the element of pressurizing the ink with spring plates before slitting them open to better distribute the ink contents on the cash. Masamichi describes a spring-loaded arm with spikes that drives into an ink pouch in Japanese Patent Application Publication No. 04098387. Abe purports to improve on this concept by pressurizing the ink pouch with a spring plate before releasing bracket that separates the ink pouch from a spike plate in U.S. Pat. No. 7,100,520.
The use of blades to puncture ink pouches can result in a simpler mechanical assembly than the use of pressured air canisters, and the above disclosures point out an advantage to pressurizing the ink pouch before puncturing to ensure thorough ink coverage within the cash compartment which the non-pressurized, gravity-fed ink deployment systems lack. The continuous pressurization of the ink pouch results, however, in the need for a strong pouch wall that will not breach prematurely under the applied pressure.
Other ink deployment schemes involve the use of fragile glass vials located near the items they are configured to devalue that are shattered by tamper attempts as taught by Lynch in U.S. Pat. No. 8,134,464. Braddick teaches a pyrotechnic chemically activated ink pouch with a coupled transceiver to initiate a reaction to release ink and smoke in U.S. Pat. No. 5,952,920. These approaches can result in dangerous glass or plastic shards mixed in with the cash, or significant destruction of the cash from fire or chemical burn.